Digital or analogue chip sound recorder schematic needed

Hello,
I would like a schematic of a simple sound recorder and player using microchips. It will be used to write and play short sound files.
I have seen the isd2560 but I was wondering of a more readily available chip version exists.
I have seen also this, EPROM AF GENERATOR by Harry Lythall which is an interesting solution with commonly available parts only for play.

Here is some for example...............

16min 16.50$
**broken link removed**

60sec 5$
**broken link removed**

120sec 10$
Special Function IC's - Others - ISD25120P

16min 13$
Special Function IC's - Others - ISD4004-16MP

More you find with google (e.g.) voice record ic

Regards KAK

Thank you, especially the 16 min version is great!

Any EPROMed solution to this? (eventhough only for playback)
I do not expect 16 mins from an eprom though.

Remember, this is only for reproducing some tones, so very good audio quality is not needed.

Here is some ideas with Eprom`s

Evertdekker.com - RC2 Decoder sound / voice playback

EPROM Sound Player

**broken link removed**

This is one of my ideas used at pre eighties
Only count addresses up with counter or CPU
R`s make simple 8bit AD, C is for filtering.

Seems to be allmost same as circuit by Harry Lythall

Click to expand...

If you are using some PIC or MCU you should think about using serial I²C bus EEPROM
or other serial mode EEPROM Ic

Parametric Product Catalog ? STMicroelectronics

**broken link removed**

By the way visit and join my group , there is some electronics info too

Regards KAK

how much time of low quality audio do you believe you can store in a 1M eprom?

I prefer the eprom version because it can be more easily interface with the ZX80 computer and the parts will be available for some decades more with some luck...

interface with the ZX80 computer

Click to expand...

understood...................

Well if we think quality of old telephone line voice band is equ. 400- 4kHz max. and we use 8 bit simple A/D.
So we read memory e.g. with 5kHz clock , it means 5kB / sec or 40kb/sec

i.e. 10sec --- 50kByte or 400kbit >>>> 1MByte --- 200sec or 1Mbit --- 25sec

This can be achieved with 4kHz lowpass filter

Maybe we can go down as 3.5kHz clock and 3kHz lo-pass , but that gonna be lo-low-quality signal.

How do you think realize interfacing with ZX , i dont remember what kind of
expansion bus was used in that machine.
C64 was the machine i used those days . Even made industrial automation and machine controls with it.

Regards KAK

Hm... that is a bit low. The 1kb internal sram can hold up to about 20sec. I was thinking of having an alternative for this old tape.
Having a way to cheat, to make the computer see this interface as a tape.
There is a better approach though if you use chips, why not to use external sram as an ssd? This will avoid having to wait for so much time for the program to load, since it will load it directly into the internal ram or read it directly into the external sram. I am not so good in digital electronics design and this is the only reason I am trying to do it using wav recording...
Everything including the schematic is explained here if you are interested **broken link removed**

Sorry my slow thoughts, it takes over night that i find out, that you
need this audio circuit for write and read programs and data with ZX80.
I try to remember how it worked those days.
I get back to this problem , when i get the idea first.

This is the principle:

ZX80 Cassette File Structure
x seconds your voice, saying "filename" (optional)
x seconds video noise
5 seconds silence
LEN bytes data, loaded to address 4000h, LEN=(400Ah)-4000h.
x seconds silence / video noise

ZX80 files do not have filenames, and video memory is not included in the file.

File End
For both ZX80 and ZX81 the file end is calculated as shown above. In either case, the last byte of a (clean) file should be 80h (ie. the last byte of the VARS area), not followed by any further signals except eventually video noise.

Bits and Bytes
Each byte consists of 8 bits (MSB first) without any start and stop bits, directly followed by the next byte. A "0" bit consists of four high pulses, a "1" bit of nine pulses, either one followed by a silence period.
0: /\/\/\/\________
1: /\/\/\/\/\/\/\/\/\________

Each pulse is split into a 150us High period, and 150us Low period. The duration of the silence between each bit is 1300us. The baud rate is thus 400 bps (for a "0" filled area) down to 250 bps (for a "1" filled area). Average medium transfer rate is approx. 307 bps (38 bytes/sec) for files that contain 50% of "0" and "1" bits each.

Regards KAK